user-manual: install user manual stylesheet with other web documents
user-manual: install user manual stylesheet with other web documents

Install the stylesheet needed for the user manual.  This should solve
the problem of, e.g.,

	http://www.kernel.org/pub/software/scm/git/docs/user-manual.html

lacking a lot of formatting.

Signed-off-by: "J. Bruce Fields" <51738506c1b2ccb0761f23bdc612c93babf738ea@citi.umich.edu>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git